RCF PRECISION TRANSDUCERS

THE TRANSDUCERS INNOVATORS

The RCF loudspeaker line incorporates a vast range of transducers covering the entire audio spectrum. We design our transducers to optimise the relationship between the purity of sound, combining the absence of distortion and the ability to withstand high power levels over a long period of time. RCF develops advanced transducer technology including the application of high-tech materials such as Neodymium, Carbon Fibre, Pure Titanium, Kevlar, Kapton and Mylar hybrids. With over 60 years of design and manufacturing experience in the market, RCF has been instrumental in technological inventions such as: carbon fibre cone moulding, double silicon spiders, inside/outside voice coil windings to edge wound voice coil manufacturing and pure titanium diaphragm forming. Our latest developments have resulted in designing state of the art neodymium magnetic circuits, radically new voice coil ventilation systems and ground breaking direct drive voice coil assemblies.

POWER HANDLING

At the core of RCF’s new transducer designs, significant amounts of time and resources were spent in terms of material science, design topology research and power testing in order to develop products with high structural strength, optimal thermal characteristics and the best possible power handling. RCF Precision engineers have developed a composite polyimide-imide former material capable of withstanding peak temperatures in excess of 380°C, well beyond the thermal requirements of modern professional audio systems. By combining this material with special adhesives, our inside-outside voice coil technology, dual silicone spiders, dual forced hyperventilation and cones based on a special fibre doping and treatment, the new RCF family of products features the industry’s most robust and reliable transducers.

NEW FERRITE MATERIAL: HIGH POWER, LOW WEIGHT MAGNETIC CIRCUIT DESIGNS

RCF Precision engineers have developed a new ferrite magnet capable of delivering higher flux in a new, minimum weight design. Thanks to this new technology, all new RCF Precision ferrite products present the minimum weight for comparable performances. New specific magnet sizes and moulds have been developed to optimise the new design performances. RCF Precision set out to develop a magnetic circuit topology capable of delivering the highest, balanced level of performance in three specific areas: maintenance of a consistent, high integrity magnetic flux gap, distortion lowering design techniques and efficient integration of the magnetic circuit in a minimum weight design. The T-pole design is optimised to generate the minimum amount of flux modulation in the magnetic assembly during typical voice coil movement within the gap.

DUAL FORCED HYPERVENTING SYSTEMS

In our complex cooling designs individual components come together to create an ideal ventilation system. Commencing with the design of the basket, RCF Precision has focused on providing finned cooling channels while optimising the surface area available in order for the front magnetic plate to dissipate heat efficiently. When assembled and placed on the basket, the front plate, ceramic core and the rear plate form part of the ventilation system that is highlighted by cooling slots precision machined through all three components. RCF Precision’s unique double silicone sealed spider design functions as an air pump expelling hot air and drawing in cool air every time the cone assembly moves. This system provides cooler operating conditions and optimal power compression. The perfect balance of noise control and quantity of the air venting the inner side of the voice coil is guarantee from a diffractor placed at the centre of the pole piece.

DIAPHRAGM ASSEMBLY

The new RCF Precision features several state of the art technologies. The diaphragm and suspension are precision formed from ultra thin pure titanium, Kapton or Mylar.

The suspension is based on an innovative design that drastically reduces distortion eliminating resonance points and assists in controlling suspension breakup modes.

This assembly delivers high power handling along with excellent mechanical and thermal properties that make RCF neodymium compression drivers robust and reliable.

PHASE PLUGS

The ND950 features a 4-slot, optimised geometry, aluminium phase plug design. Extensive computer assisted mathematical modelling and testing has resulted in a phase plug geometry that provides balanced acoustic performance by controlling and lowering air distortion and maximizing output. This permits the use of a lower phase plug slot compression ratio that generates substantially lower distortion artefacts. The result is high output with smooth acoustic frequency response and low harmonic distortion artefacts. Our compression drivers features 3-slot, 2-slot and radial optimised geometry phase plug designs. Extensive computer assisted mathematical modelling and testing has resulted in phase plug geometries that provide balanced acoustic performance by controlling and lowering air distortion.

MAGNETIC CIRCUITS

RCF Precision Neodymium magnetic circuit designs provide even higher magnetic field strength in the voice coil gap than standard ceramic assemblies while dramatically lowering the overall weight of the device. Neodymium rare earth material also provides higher levels of force (BL) that increase control of the dome assembly’s moving mass. This leads to higher efficiency, better transient response and diminishes high frequency distortion modes. RCF’s new ferrite magnetic circuit design is optimised to offer the highest possible magnetic field strength achievable in the voice coil gap, providing the required force to precisely control the dome assembly’s moving mass. A thin copper ring is precision pressed onto the pole piece in order to modify and lower the inductance characteristics of the magnetic circuit and voice coil, thus providing a controlled extension of the acoustic frequency response. RCF Precision has provided cooling fins on the rear of the aluminium diaphragm assembly cover that creates a heat dissipating surface area for the driver’s magnetic circuit. This assists in lowering circuit temperature, improving the driver’s power compression characteristics and increasing output.

INSIDE/OUTSIDE VOICE COILS

RCF has developed a unique voice coil, combining the advantages of inside/outside technology with the superior quality of polyimideimide materials (wire resins and formers resins). The inside/outside coil offers many advantages: the dissipation surface is doubled; the adhesion area to the Former is doubled; during thermal expansion the Former is squeezed between inside and outside layers offering the best mechanical resistance. Our inside/outside formers are made from polyimide-imide fibreglass and the area between the coil and the cone is a triple layer of Nomex - Fibreglass - Nomex for maximum stiffness and accurate sound transfer.

DUAL SILICONE SPIDERS

RCF’s original invention of the dual silicone sealed spider design offers many advantages: the two spiders offer double resistance to fatigue; the silicone between the cloth layers, being a very high memory material, provides the best shape stability to the spiders; the system, being sealed, functions as an air pump expelling hot air and drawing in cool air every time the cone assembly moves.

EDGEWOUND COILS

Edge-wound flat wire voice coils are a hallmark of advanced manufacturing. RCF produces in-house all the flat wire voice coils used in its compression drivers. To guarantee the ultimate level of performance and reliability, maximum care in material selection and process design is combined with extensive use of quality control and power testing procedures. Each driver is thoroughly tested for frequency response, impedance and distortion with DSP enabled digital testing equipment. The result is a robust device capable of withstanding the rigors of modern loudspeaker system applications.

MECHANICAL DESIGN

RCF Precision has also invested countless hours addressing mechanical design issues. Connection of lead wires is improved through the design of a specific spoke capable of providing a safe and larger excursion in a noiseless and safe side connection. Baskets are designed to provide the maximum strength, the lightest weight, while minimizing overall diameter and maximizing cone piston diameter.